Integrated power plants which utilize coal and especially lignite or low-value coals as a basis, are known (see German patent 36 44 192), such coal-fired plants being provided as so-called major power plants with outputs in the megawatt range. They can be provided as so-called combination or integrated power plants in which a coal gasifying unit is integrated with a gas turbine main unit, a steam turbine main unit and an electricity-generating main unit driven by one or both of those turbine units.
A major power plant of this type can also be utilized in combination with at least one relatively more remote satellite power plant which may be located closer to the consuming region than the main power plant.
A satellite power plant of this type can comprise a gas turbine unit and an electric current generating unit. The waste heat from the gas turbine main unit of the combination or integrated power plant is supplied to the steam turbine cycle in which a portion of the steam, to utilize its sensible heat, can be supplied to the coal gasifier.
The coal gasifier generally is operated to supply fuel gas quantities which are called for by the demand of the gas turbine main unit of the power plant and an excess can be supplied to the satellite power plant.
In this manner it is possible to achieve a very high utilization of the heat generated by the fuel and, at the same time, obtain a high conversion of the thermal energy of the fuel to electrical energy.
However, there is not always a need at any particular place for a major power plant of the combination type described above, and it is possible that a satellite power plant or a number of satellite power plants which may have outputs of an order of magnitude less than the major power plant, can satisfy the requirements of a particular region.
In those cases, it is uneconomical and undesirable to erect a major power plant at these locations.
It has been a practice heretofore, however, not to provide satellite-type power plants independently of the major power plants, but rather to utilize small independent generating systems, i.e. so-called free-standing power plants in these areas.
However, in regions in which future industrialization or other prognoses of the socioeconomic factors indicate that a major power plant will be required in the future, these completely independent power generating units may ultimately prove to be uneconomical and undesirable as compared with satellite and major power plant systems.